USGS Water-Year Summary 2024

11276600 Tuolumne River above Early Intake, near Mather, CA

LOCATION - Lat 37°52'46", long 119°56'46" referenced to North American Datum of 1927, in SE 1/4 SW 1/4 sec.01, T.1 S., R.18 E., Tuolumne County, CA, Hydrologic Unit 18040009, in Stanislaus National Forest, on right bank, 0.5 mi upstream from Early Intake, 2.4 mi upstream from Cherry Creek, and 5.0 mi west of Mather.

DRAINAGE AREA - 484 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1970 to current year.

GAGE - Water-stage recorder. Elevation of gage is 2,420 ft above NGVD of 1929, from topographic map. Prior to Sept. 5, 2007, at site on left bank.

REMARKS - Flow regulated by Hetch Hetchy Reservoir (station 11275500) 12 mi upstream. Flow diverted upstream from station through tunnel to Robert C. Kirkwood Powerplant and Hetch Hetchy Aqueduct. See schematic diagram of Tuolumne River Basin available from the California Water Science Center.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood of June 1, 1943, reached a stage of 22.1 ft, discharge, 12,900 ft³/s.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 17,700 ft³/s, Jan. 3, 1997, gage height, 22.98 ft; minimum daily, 25 ft³/s, Oct. 11, 1988.

WATER-QUALITY RECORDS

PERIOD OF RECORD -

CONTINUOUS WATER-QUALITY DATA:
WATER TEMPERATURE: Water years October 1971 to June 1972, August 1987 to current year (water years 1972, 1987-2023, daily).

INSTRUMENTATION - Water-temperature recorder October 1971 to June 1972, and since Aug. 12, 1987. Prior to Sept. 5, 2007, at site 600 ft upstream.

REMARKS -